Windows are hard to resize with mouse

[moonlitpath]

The area where you can click and drag on window borders is too thin, about 1px wide.

[TheKodeToad]

Personally I found even with the accessibility variant of the xfwm theme it is very frustrating to resize a window without using your keyboard

[ak-li]

I use Greybird under XFCE and can only confirm the statements of @moonlitpath and @TheKodeToad.

My solution was to change the image files

bottom-active.xpm
bottom-left-active.xpm
bottom-right-active.xpm
left-active.xpm
right-active.xpm
bottom-inactive.xpm
bottom-left-inactive.xpm
bottom-right-inactive.xpm
left-inactive.xpm
right-inactive.xpm

under

/usr/share/themes/Greybird/xfwm4/
/usr/share/themes/Greybird-dark/xfwm4/ 
/usr/share/themes/Greybird-accessibility/xfwm4/
/usr/share/themes/Greybird-dark-accessibility/xfwm4/

to a size of 5 resp.8 px.

The screens used have a resolution of 1680x1050 and 1920x1080